The present invention relates to a storage system, in particular to a storage system configured to provide a reliable data archiving capability.
Data archival is the act of saving a specific version of a data set (e.g., for record retention purposes) for an extended period of time. The data set is stored in archive storage pursuant to command by a user or data processing administrator. Archived data sets are often preserved for legal purposes or for other reasons of importance to the data processing enterprise. Accordingly, it should be possible to verify that the archived data have not be altered, tempered, or rewritten once the data have been written. One method for providing data verification or certification is to use Write Once and Read Many (WORM) techniques.
As the term suggest, the WORM technique enables data to be written only once to the storage medium, e.g., optical storage device or WORM discs. Such WORM discs generally can be written only once because the medium is physically and permanently modified by the process of writing data thereto, e.g., by using a high power laser beam to form small pits which alter the reflectance of the surface of the medium. The read process can then retrieve the stored information many times thereafter by beaming a low power beam on the medium and detecting the reflectance of the low power beam.
The WORM technique has gained more importance recently with the new government regulations requiring companies to preserver certain business records in a non-rewritable, non-erasable format. For example, U.S. Securities and Exchange Commission has recently required stock brokers to preserve records of communications with their customers in a non-rewritable, non-erasable format under the Securities Exchange Act of 1934 Rule 17a-4. The National Association of Securities Dealers Inc. (NASD) has implemented similar regulations in Rule 3010 & 3110. These communications include emails, instant messages and voice messages, and constitute a tremendous amount of data.
One method of providing WORM storage procedure is to use File System's change mode functions like “chmod” in UNIX, which designates certain files as being non-rewritable. However, this method does not provide sufficient trusts to auditor since it is based on generally available software.
The method also requires a significant administrative burden to users, such as changing modes to each file.
Alternatively, WORM storage devices, e.g., CD-ROM and DVD-ROM, may be used. However, these WORM devices generally do not provide high speed write operations. If they are used to archive the required communications between the customers and the business, a significant performance delay would result.
Yet another method would be to use a disc array storage unit that are provided with internal WORM capabilities. Such a storage unit may be provided with micro-programs inside their controller with a WORM capability. This method would use a specific software program that users can not access in order to provide more trust to the auditors. However, this method would require high development costs.
Accordingly, it would be desirable to provide a WORM archiving system that provides a high degree of trust, ease of management, limited performance impacts, and low implementation cost, particularly a system that enables a WORM verification or proving feature.